This Graphics.drawImage method expects an ImageObserver instead of your Stage object.Your Stage interface is not an ImageObserver. You import it, but that is just a compiler directive, your code does nothing with the import.

By decent I mean it's up with today's standard and not '84, when people where still happy doing awkward things in a console.In this particular case I'm refering to error highlighting, the compiler will tell you the line and char of where the offending token is but in any decent IDE it will show you as you type much like a Text editors spell check. Which should have allowed you to pick out the mistake yourself. Moreover it will probably say exactually the same replied here albeit a maybe little more cryptic.

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